Exponent of 2 in prime factorization of prime(n) - 1.

Terms

a(0) =0a(1) =1a(2) =2a(3) =1a(4) =1a(5) =2a(6) =4a(7) =1a(8) =1a(9) =2a(10) =1a(11) =2a(12) =3a(13) =1a(14) =1a(15) =2a(16) =1a(17) =2a(18) =1a(19) =1a(20) =3a(21) =1a(22) =1a(23) =3a(24) =5a(25) =2a(26) =1a(27) =1a(28) =2a(29) =4